This article tells the story of the prosecution of a master for the torture of two female slaves suspected of using poison in pre-revolutionary Saint-Domingue (Haiti): the so-called Lejeune affair of 1788. The case illustrates how a terror-torture nexus, rooted in an early modern anxiety about the crisis-prone nature of slave societies and fueled by deep-seated planter fears of a slave revolution, complicated the administration of plantation life in this Old Regime French colony. Slave law assumed the precautionary task of counteracting the tendency towards planter brutality that inhered in the master-slave relationship, purportedly demonstrating to slaves that they too enjoyed the protection of royal authority. In response, the defendant in the case argued that his prosecution would only further fan the flames of slave resistance. Dramatizing as it does the development of a strategic or commonwealth ethics of colonial administration, the Lejeune affair underscores the interpretive limits of the standard, functionalist definition of torture as a technique used by state actors to investigate crime. And it suggests that colonial slave law, by the very act of encountering its own preemptive limits, generated ideological pressures that militated against (and not only for) the continuation of plantation slavery.